Generally, a washing machine refers to an electrical household product constructed to remove various contaminants from clothes, bedclothes and the like by employing the emulsification of detergent, rubbing action and impact action, which are applied to laundry by water streams generated by the rotation of a pulsator or a drum, and the like. Fully-automatic washing machines, which have recently been proposed, are constructed to automatically perform a series of courses composed of a washing course, a rinsing course, a dewatering course and the like, without the need for intervening manipulation on the part of the user.